Spinal implant locking member with improved guidance, tactile and visual feedback

Abstract

An implant having a receiver that is adapted to receive a polyaxial screw in the bore and either an internal or external cap. The cap can be an external or internal cap and the implant further has at least one locking aid in the form of at least one of a tactile feedback, a visual feedback or an enhanced fixation between the cap and a rod that is received in the receiver.

What is claimed is: 
     
       1. An implant comprising:
 a receiver having at least one internal wall defining a bore, at least a portion of said receiver having a receiver thread, said receiver further comprising a rod-receiving channel in communication with said bore, said rod-receiving channel being adapted to receive a rod; 
 a polyaxial screw for receipt in said bore; 
 a cap having a cap thread for mating with said receiver thread to permit said cap to be screwed on said receiver in order to lock said rod in said rod-receiving channel of said receiver; and 
 a lock aid associated with at least one of said receiver or said cap; 
 said lock aid comprising an indicia generally aligned with a leading edge of said cap thread or said receiver thread; 
 at least one of said receiver thread or said cap thread being defined by a male thread, a leading portion of said male thread being truncated or cut out to provide at least one of a tactile or a visual feedback; 
 wherein said cap comprises a deformable area adapted to provide said lock aid, said deformable area engaging said rod and deforming on it after said rod is received in said receiver and said cap is rotated and screwed on said receiver; 
 wherein said male thread and said deformable area are monolithic and are integrally formed in a rod-engaging end of said cap. 
 
     
     
       2. The implant as recited in  claim 1  wherein said receiver thread is defined by a female thread, a leading portion of said female thread being truncated or cut out and adapted to define said lock aid. 
     
     
       3. The implant as recited in  claim 2  wherein said leading portion of said female thread of said receiver and said leading portion of said a male thread of said cap each being truncated and adapted so that when said leading portions are adjacent each other and initially pass each other when said cap is mounted on said receiver, said leading portions move relative to each other a drop-down distance that is greater than or equal to at least one thread pitch. 
     
     
       4. The implant as recited in  claim 2  wherein said leading portion of said female thread lies along a first radial line that is generally perpendicular to an axis of said receiver and said leading portion of said male thread lies along a second radial line that is generally perpendicular to an axis of said receiver, said first and second radial lines being generally parallel when said leading portions initially align when said cap is mounted on said receiver. 
     
     
       5. The implant as recited in  claim 1  wherein said receiver thread comprises at least a portion having a thread depth that is greater than a thread width, both of which are adapted to define said lock aid. 
     
     
       6. The implant as recited in  claim 1  wherein said rod-receiving channel comprises a first rod-receiving opening and a generally opposed second rod-receiving opening in said receiver, said at least one internal wall comprising a first arcuate wall between said first and second rod-receiving openings and a second arcuate wall that generally opposes said first arcuate wall, said first arcuate wall having first arcuate wall threads and said second arcuate wall having second arcuate wall threads, said first and second arcuate wall threads cooperating to define said receiver thread,
 said first arcuate wall threads having a starting thread that is shorter than at least one other of said first arcuate wall threads to define a cut-out zone for facilitating receiving a starting thread of said cap thread, thereby providing said tactile feedback when said cap is received on said receiver, said first and second arcuate wall threads cooperating with said cap thread to provide said lock aid. 
 
     
     
       7. The implant as recited in  claim 1  wherein said receiver threads comprises at least a portion having a thread depth that is greater than at least one of a thread width or pitch and being adapted to define said lock aid. 
     
     
       8. The implant as recited in  claim 1  wherein said cap thread define at least one male thread having a starting end, said cap further comprising an indicia on a surface that provides notice of said starting end, said indicia being adapted to define said lock aid. 
     
     
       9. The implant as recited in  claim 8  wherein said indicia is a line on a top surface of said cap, said line being generally aligned with said starting end. 
     
     
       10. The implant as recited in  claim 1  wherein at least a portion of said receiver thread is adapted on said receiver to permit a start of said cap thread and said cap to drop down a drop down distance in said receiver, said drop down distance being selected to define said lock aid. 
     
     
       11. The implant as recited in  claim 10  wherein said drop down distance is greater than or equal to the distance of a pitch between adjacent threads of receiver thread. 
     
     
       12. The implant as recited in  claim 2  wherein said receiver thread are integral with said at least one internal wall and said cap thread is on an inner diameter surface of the cap so that the cap can be screwed onto an outer surface of said receiver, said cap having an integral deformable ring on a bottom surface of said cap. 
     
     
       13. The implant as recited in  claim 1  wherein said cap has a surface adapted to provide said lock aid by facilitating guiding said cap on said receiver to facilitate aligning said cap thread with said receiver thread so that said cap can be screwed on said receiver. 
     
     
       14. The implant as recited in  claim 13  wherein said surface is curved, arcuate, frusto-conical or semi-spherical and situated on an end of said cap, said surface being adapted to engage an open end of said receiver and guide said cap thread toward and into engagement with said receiver thread. 
     
     
       15. The implant as recited in  claim 1  wherein said deformable area becomes cold welded on said rod when said cap has been screwed on said receiver in less than or equal to one revolution after initial rod contact. 
     
     
       16. The implant as recited in  claim 1  wherein said deformable area is a ring in a rod-engaging end of said cap. 
     
     
       17. The implant as recited in  claim 16  wherein said ring is a monolithic ring integrally formed in said rod-engaging end of said cap. 
     
     
       18. The implant as recited in  claim 1  wherein said cap comprises an aperture in a rod-engaging end, said cap having a monolithic and deformable ring surrounding said aperture that is adapted to provide said lock aid, said monolithic and deformable ring engaging said rod and deforming on it after said rod is received in said receiver and said cap is screwed on said receiver. 
     
     
       19. The implant as recited in  claim 18  wherein said cap comprises a generally planar cap bottom, said monolithic and deformable ring being generally perpendicular to said generally planar cap bottom. 
     
     
       20. The implant cap as recited in  claim 19  wherein said generally planar cap bottom and said monolithic and deformable ring have a diameter smaller than that of the overall cap diameter. 
     
     
       21. The implant as recited in  claim 18  wherein said rod-engaging end of said cap comprises a frusto-conical shape, said monolithic and deformable ring being integral with an end of said frusto-conical shape. 
     
     
       22. The implant as recited in  claim 2  wherein said deformable area is a ring formed in a rod-engaging end of said cap. 
     
     
       23. The implant as recited in  claim 22  wherein said ring is a monolithic ring formed in said rod-engaging end of said cap. 
     
     
       24. The implant as recited in  claim 23  wherein said rod-engaging end of said cap comprises a frusto-conical shape, said monolithic ring is integral with an end of said frusto-conical shape. 
     
     
       25. An implant cap for mounting on an implant receiver that receives and supports a rod in a rod-receiving area of said implant receiver and that has receiver threads, said implant cap comprising:
 a body having an area for receiving a tool for rotatably driving said implant cap; 
 a cap thread for cooperating with said receiver thread to permit said implant cap to be screwed and mounted on or in said implant receiver in order to lock said rod in the rod-receiving area of said implant receiver; and 
 a lock aid comprising an indicia on said implant cap generally aligned with a leading edge of said cap thread; 
 said cap thread being defined by a male thread, a leading portion of said male thread being truncated or cut out to provide at least one of a tactile feedback or visual feedback; 
 wherein said implant cap comprises a deformable area adapted to provide said lock aid, said deformable area engaging said rod and deforming on it after said rod is received in said receiver and said implant cap is rotated and screwed on said receiver; 
 wherein said male thread and said deformable area are monolithic and integrally formed in a rod-engaging end of said implant cap. 
 
     
     
       26. The implant cap as recited in  claim 25  wherein said lock aid comprises indicia on a surface that provides notice of a starting end of said cap thread. 
     
     
       27. The implant cap as recited in  claim 26  wherein said indicia is a line on a top surface of said implant cap, said line being generally aligned with said starting end. 
     
     
       28. The implant cap as recited in  claim 25  wherein said implant cap has a surface, said surface facilitating guiding said body on said implant receiver to facilitate aligning said cap thread with said receiver thread so that said implant cap can be screwed on said implant receiver. 
     
     
       29. The implant cap as recited in  claim 28  wherein said surface is a frusto-conical, arcuate, curved or semispherical at an end of said implant cap. 
     
     
       30. The implant cap as recited in  claim 25  wherein said body comprises a deformable area that deforms on said rod after said rod is received in said implant receiver and said implant cap is screwed on said implant receiver. 
     
     
       31. The implant cap as recited in  claim 30  wherein said deformable area is a ring in a rod-engaging end of said implant cap. 
     
     
       32. The implant cap as recited in  claim 31  wherein said ring is a monolithic ring integrally formed in said rod-engaging end of said implant cap. 
     
     
       33. The implant cap as recited in  claim 25  wherein said implant cap comprises an aperture in a rod-engaging end, said implant cap having a monolithic and deformable ring surrounding said aperture, said monolithic and deformable ring engaging said rod and deforming on it after said rod is received in said implant receiver and said implant cap is screwed on said implant receiver. 
     
     
       34. The implant cap as recited in  claim 33  wherein said implant cap comprises a cap bottom, said monolithic and deformable ring being generally opposed to said cap bottom. 
     
     
       35. The implant cap as recited in  claim 34  wherein said cap bottom is generally planar and said monolithic and deformable ring is generally perpendicular to said cap bottom. 
     
     
       36. The implant cap as recited in  claim 35  wherein said generally planar cap bottom and said monolithic and deformable ring have a diameter smaller than that of the overall cap diameter. 
     
     
       37. The implant cap as recited in  claim 33  wherein said rod-engaging end of said implant cap comprises a frusto-conical, semi-spherical, arcuate or curved shape, said monolithic and deformable ring being integrally formed in said rod-engaging end. 
     
     
       38. An implant comprising:
 a receiver having a at least one internal wall defining a bore, at least a portion of said receiver having a receiver thread, said receiver further comprising a rod-receiving channel in communication with said bore, said rod-receiving channel being adapted to receive a rod; 
 a polyaxial screw for receipt in said bore; 
 a cap having a cap thread for mating with said receiver thread to permit said cap to be screwed on said receiver in order to lock said rod in said rod-receiving channel of said receiver; and 
 said receiver thread is defined by a female thread, a leading portion of said female thread being truncated or cut out 
 an indicia on said cap, said indicia being generally aligned with a leading edge of said cap thread; 
 said cap thread being defined by a male thread, a leading portion of said male thread being truncated or cut out to provide at least one of a tactile feedback or a visual feedback; 
 wherein said cap comprises a deformable area adapted to provide a lock aid, said deformable area engaging said rod and deforming on it after said rod is received in said receiver and said cap is rotated and screwed on said receiver; 
 wherein said male thread and said deformable area are monolithic and integrally formed in a rod-engaging end of said cap. 
 
     
     
       39. The implant as recited in  claim 38  wherein said cap thread is defined by a male thread, a leading portion of said male thread being truncated or cut out. 
     
     
       40. The implant as recited in  claim 39  wherein said leading portion of a female thread of said receiver and said leading portion of said a male thread of said cap each being truncated and adapted so that when said leading portions are adjacent each other and initially pass each other when said cap is mounted on said receiver, said leading portions move relative to each other a distance that is greater than or equal to the distance of a pitch between adjacent threads of receiver thread. 
     
     
       41. The implant as recited in  claim 40  wherein said leading portion of said female thread lies along a first radial line that is generally perpendicular to an axis of said cap and said leading portion of said male thread lies along a second radial line that is generally perpendicular to an axis of said receiver, said first and second radial lines being generally parallel when said leading portions initially engage when said cap is mounted on said receiver. 
     
     
       42. The implant as recited in  claim 38  wherein said female thread comprises at least a portion having a thread depth that is greater than a thread width. 
     
     
       43. The implant as recited in  claim 38  wherein said rod-receiving channel comprises a first rod-receiving opening and a generally opposing second rod-receiving opening that define a first arcuate wall between said first and second rod-receiving openings and a second arcuate wall that generally opposes said first arcuate wall, said first rod-receiving opening and said second rod-receiving opening interrupting said receiver thread to provide first arcuate wall threads in said first arcuate wall and second arcuate wall threads in said second arcuate wall, said first and second arcuate wall threads cooperating to define said receiver thread,
 said first arcuate wall threads having a starting thread that is shorter than at least one other of said first arcuate wall threads to define a cut-out zone for facilitating receiving a starting thread of said cap thread, thereby providing tactile feedback when said cap is received on said receiver, said first and second arcuate wall threads cooperating with said cap thread. 
 
     
     
       44. The implant as recited in  claim 38  wherein said receiver threads comprises at least a portion having a thread depth that is greater than at least one of a thread width or pitch. 
     
     
       45. The implant as recited in  claim 38  wherein said cap thread define at least one male thread having a starting end, said cap further comprising an indicia on a surface that provides notice of said starting end. 
     
     
       46. The implant as recited in  claim 45  wherein said indicia is a line on a top surface of said cap, said line being generally aligned with said starting end. 
     
     
       47. The implant as recited in  claim 38  wherein at least a portion of said receiver thread is adapted on said receiver to permit a start of said cap thread and said cap to drop down a drop down distance in said receiver, said drop down distance being greater than a pitch of said receiver thread. 
     
     
       48. The implant as recited in  claim 47  wherein said drop down distance is greater or equal to a distance associated with at least one thread of a pitch between adjacent threads of said receiver. 
     
     
       49. The implant as recited in  claim 38  wherein said receiver thread are integral with said at least one internal wall and said cap thread or on an outer diameter of the cap so that the cap can be screwed into said bore. 
     
     
       50. An implant comprising:
 a receiver having at least one internal wall defining a bore, at least a portion of said receiver having a receiver thread, said receiver further comprising a rod-receiving channel in communication with said bore, said rod-receiving channel being adapted to receive a rod; 
 a polyaxial screw for receipt in said bore; 
 a cap having a cap thread for mating with said receiver thread to permit said cap to be screwed on said receiver in order to lock said rod in said rod-receiving channel of said receiver; and 
 said cap comprising a surface for facilitating guiding said cap on said receiver and aligning said cap thread with said receiver thread so that said cap can be screwed on said receiver; 
 wherein said cap comprises a deformable area that is monolithic or integral with said cap and that is adapted to engage said rod and deform on it after said rod is received in said receiver and said cap is screwed on said receiver; 
 wherein said surface is frusto-conical or semi-spherical and comprises said deformable area that is monolithic or integral therewith. 
 
     
     
       51. The implant as recited in  claim 50  wherein said surface is situated on an end of said cap. 
     
     
       52. The implant as recited in  claim 50  wherein said cap comprises a deformable area, said deformable area engaging said rod and deforming on it after said rod is received in said receiver and said cap is screwed on said receiver. 
     
     
       53. The implant as recited in  claim 52  wherein said deformable area becomes cold welded on said rod when said cap has been screwed on said receiver in less than or equal to one revolution after initial rod contact. 
     
     
       54. The implant as recited in  claim 53  wherein said deformable area is a ring in a rod-engaging end of said cap. 
     
     
       55. The implant as recited in  claim 54  wherein said ring is a monolithic ring integrally formed in said rod-engaging end of said cap. 
     
     
       56. The implant as recited in  claim 55  wherein said monolithic ring has a width of between 0.120-0.280 inches. 
     
     
       57. The implant as recited in  claim 50  wherein said cap comprises an aperture in a rod-engaging end, said cap having a monolithic and deformable ring surrounding said aperture, said monolithic and deformable ring engaging said rod and deforming on it after said rod is received in said receiver and said cap is screwed on said receiver. 
     
     
       58. The implant as recited in  claim 57  wherein said cap comprises an annular cap seat, said monolithic and deformable ring being generally parallel to said annular cap seat. 
     
     
       59. The implant cap as recited in  claim 58  wherein said annular cap seat and said monolithic and deformable ring have a diameter smaller than that of the overall cap diameter. 
     
     
       60. An implant comprising:
 a receiver having a at least one internal wall defining a bore, at least a portion of said receiver having a receiver thread, said receiver further comprising a rod-receiving channel in communication with said bore, said rod-receiving channel being adapted to receive a rod; 
 a polyaxial screw for receipt in said bore; and 
 a cap having a cap thread for mating with said receiver thread to permit said cap to be screwed on said receiver in order to lock said rod in said rod-receiving channel of said receiver; 
 said cap comprises a deformable area adapted to engage said rod and deforming on it after said rod is received in said receiver and said cap is screwed on said receiver; 
 wherein said deformable area and said cap thread are monolithically or integrally formed in said cap so that said cap thread and said deformable area are a one-piece construction. 
 
     
     
       61. An implant comprising:
 a receiver having a at least one internal wall defining a bore, at least a portion of said receiver having a receiver thread, said receiver further comprising a rod-receiving channel in communication with said bore, said rod-receiving channel being adapted to receive a rod; 
 a polyaxial screw for receipt in said bore; and 
 a cap having a cap thread for mating with said receiver thread to permit said cap to be screwed on said receiver in order to lock said rod in said rod-receiving channel of said receiver; 
 said cap comprises a deformable area adapted to engage said rod and deforming on it after said rod is received in said receiver and said cap is screwed on said receiver; 
 wherein said deformable area is monolithically or integrally formed in said cap so that said cap thread and said deformable area are a one-piece construction; 
 wherein said deformable area becomes cold welded on said rod when said cap has been screwed on said receiver in less than or equal to one revolution after initial rod contact. 
 
     
     
       62. The implant as recited in  claim 60  wherein said deformable area is a ring in a rod-engaging end of said cap. 
     
     
       63. The implant as recited in  claim 62  wherein said ring is a monolithic ring integrally formed in said rod-engaging end of said cap. 
     
     
       64. The implant as recited in  claim 63  wherein said monolithic ring has a width of between 0.120-0.280 inches. 
     
     
       65. The implant as recited in  claim 60  wherein said cap comprises an aperture in a rod-engaging end, said cap having a monolithic and deformable ring surrounding said aperture, said monolithic and deformable ring engaging said rod and deforming on it after said rod is received in said receiver and said cap is screwed on said receiver. 
     
     
       66. The implant as recited in  claim 65  wherein said cap comprises an annular cap seat, said monolithic and deformable ring being generally parallel to said annular cap seat. 
     
     
       67. The implant cap as recited in  claim 66  wherein said annular cap seat and said monolithic and deformable ring have a diameter smaller than that of the overall cap diameter.